Manufacture of spray-dried detergents containing sodium tripolyphosphate

ABSTRACT

Sodium tripolyphosphate-containing detergents are produced by the spray-drying of a spray slurry containing the detergent components, the slurry being prepared with the use of sodium tripolyphosphate formed at least partially of material with a crystal water content between a maximum of less than 22.7 percent by weight and a minimum of 17.0 percent by weight.

United States Patent 151 3,639,287

Gabler et al. [451 1.211222 7 [54] MANUFACTURE OF SPRAY-DRIED DETERGENTS CONTAINING SODIUM TRIPOLYPHOSPI-IATE Inventors: l-lellmut Gabler, Morlenbach; Heinz Harnisch, Weiden-Lovenich; Gero I-Ieymer, Knapsack near Cologne; Karl Merkenich, Hurth near Cologne; Wolf-Dieter Pirig, Eusk irchen, all of Germany I I Assignee: Knapsack Aktiengesellschaft, Knapsack bei Cologne, Germany Filed: Aug. 16, 1967 Appl. No.: 660,928

Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 3,334,049 8/1967 Versen ..252/I35 FOREIGN PATENTS OR APPLICATIONS 988,058 4/ 1965 Great Britain ..252/ l 35 Primary Examiner-Herbert B, Guynn Assistant Examiner-Dennis L. Albrecht Attorney-Connolly and Hutz [57] ABSTRACT Sodium tripolyphosphate-containing detergents are produced by the spray-drying of a spray slurry containing the detergent components, the slurry being prepared with the use of sodium tripolyphosphate formed at least partially of material with a crystal water content between a maximum of less than 22.7 percent by weight and a minimum of 17.0 percent by weight.

3 Claims, No Drawings MANUFACTURE OF SPRAY-DRIED DETERGENTS CONTAINING SODIUM TRIPOLYPHOSPHATE The present invention relates to a process for the manufacture of detergents containing sodium tripolyphosphate, by spray-drying a spray slurry including the detergent components.

Sodium tripolyphosphate is known to increase the viscosity of detergent slurries. This is the result of the hydration sodium tripolyphosphate undergoes to form the hexahydrate. 1n the production of detergents, attempts are being made with the object of transforming quantitatively the sodium tripolyphosphate into hexahydrate, so as to enable the slurry, which is sprayed while hot, to produce a final product of good flow properties and stability to storage.

When phase-ll sodium tripolyphosphate is used, the hydration is found to proceed very reluctantly and to be accompanied by a low viscosity increase. This means rather long stirring periods for quantitative hydration of the tripolyphosphate. Sodium tripolyphosphate containing phasel undergoes hydration more rapidly than phase-ll and therefore forms the hexahydrate substantially more rapidly, which means shorter stirring periods for the slurry. However, the use of sodium tripolyphosphates containing phase-l is accompanied by a considerable viscosity increase of the slurry, which is the more rapid the higher the phase-l content of the tripolyphosphate. The sodium tripolyphosphates customarily used have a phase-l content between 15 and 45 percent. in view of the fact, however, that detergent slurries, depending on the type of finishing treatment, are known to have a processability limited in each particular case by a given maximum viscosity which, in the spray process, is determined by the spray facilities, it is clear that the tripolyphosphate is not allowed to contain phase-I material in a proportion beyond a certain upper limit. High phase-l contents are furthermore found to tend to lump formation in the slurry.

In an attempt to obviate these difficulties, it has already been proposed to prepare detergent slurries with sodium tripolyphosphate which is at least partially in the form of the hexahydrate.

The disadvantage associated with this process resides in the fact that the Na,P O has to be used at least partially in the form of material adjusted to have a definite water content of 22.7 percent by weight, corresponding to that of the hexahydrate. Needless to say the production of sodium tripolyphosphate adjusted to have exactly that water content calls for the use of special steps and very specific conditions.

It has now unexpectedly been found that sodium tripolyphosphate formed at least partially of material with a crystal water content between a maximum or less than 22.7 percent by weight and a minimum of 17.0 percent by weight, can be used for making detergents slurries with constant, low viscosity, in which the sodium tripolyphosphate practically does not hydrolyze, even after prolonged standing.

In other words, the present invention enables the use of sodium tripolyphosphate with a water content variable within a range of about 5.7 percent, which can be produced considerably more readily.

The sodium tripolyphosphate having a water content such as proposed in accordance with the present invention, should be used in a proportion of at least 5 percent by weight, preferably 50 to 100 percent by weight, referred to the total quantity of sodium tripolyphosphate. Apart from sodium tripolyphosphate, the detergent slurry may contain further condensed and, if desired, anhydrous phosphates, such as sodium pyrophosphate or sodium metaphosphate. The detergent slurry, which should conveniently contain a total of to 50 percent by weight sodium tripolyphosphate, can be prepared at temperatures between 20 and 90 C., preferably between 40 and 60 C.

The following examples illustrate the process of-the present invention:

EXAMPLE l Time in minutes: 0 I0 20 30 40 50 60 Knead resistance 0 0.05 0.06 0.09 0.] 0| 0.]

in mkp:

Hydrolysis. referred to anhydrous minutes: 30 60 EXAMPLE 2 (Conventional process) A detergent slurry containing 60 percent by weight solid matter and composed of:

20 grams alkyl-aryl-sulfonate 57.7 grams sodium tripolyphosphate hexahydrate 6 grams sodium silicate 4 grams magnesium silicate 5 grams sodium sulfate 1 gram carboxy-methyl-cellulose 4 l .3 grams water was tested to determine the knead resistance as a function of time, at a temperature of 60 C.

Time in minutes: 0 I0 20 30 40 50 60 Knead resistance 0 0.02 0.02 0.02 0.02 0.02 0.02

in mkp:

ydrolysis, referred to anhydro s u iuafter minutes: 30 60 EXAMPLE 3 (Process of invention) A detergent slurry containing 60 percent by weight solid matter and composed of:

20 grams alkyl-aryl-sulfonate 45 grams sodium tripolyphosphate 18 percent H 0) 6 grams sodium silicate 4 grams magnesium silicate 5 grams sodium sulfate 1 gram carboxy-methyl-cellulose 54 grams water was tested to determine the knead resistance as a function of time, at a temperature of 60 C.

Time in minutes: 0 -l0 20- 30 40 $0 60 Knead resistance 0 0.02 0.02 0.02 0.02 0.02 0.02

in mkp:

Hydrolysis, referred to anhydrous minutes: 30 60 EXAMPLE 4 (Process of invention) A detergent slurry containing 60 percent by weight solid matter and composed of:

20 grams alkyl-aryl-sulfonate 45 grams sodium tripolyphosphate (20 percent H 0) 6 grams sodium silicate 4 grams magnesium silicate grams sodium sulfate 1 gram carboxy-methyl-cellulose 54 grams water was tested to determine the knead resistance as a function of time, at a temperature of 60 C. I

Time in minutes: 0

Knead resistance 0 002 0.02 002 0.02 0.02 0.02 in nikp:

Hydrolysis, referred to anhydrous minutes: 30 60 We claim:

1. In the process for the manufacture of detergent compositions by spray-drying an aqueous detergent slurry the components of which include sodium tripolyphosphate and an organic detergent, the improvement which comprises preparing the said slurry by mixing sodium tripolyphosphate, all of which has a crystal water content from 18m 20 weight percent, the

said sodium tripolyphosphate being used in aproportion of 

2. The process of claim 1 wherein the aqueous slurry is prepared at a temperature between 40* and 60* C.
 3. In the process of claim 1 including in the detergent components in addition to the said sodium tripolyphosphates at least one member selected from the group consisting of sodium pyrophosphate and sodium metaphosphate. 